[5+1] Annulation of aza‐<i>o</i>‐Quinone Methides with Primary Amines: Construction of 3,4‐Dihydroquinazolin‐2(1<i>H</i>)‐One Derivatives

Abstract A [5+1] annulation between in situ generated aza‐ o ‐quinone methides and primary amines has been developed. This methodology offers efficient access to diverse 3,4‐dihydroquinazolin‐2(1 H )‐one derivatives with yields ranging from 45 % to 99 %. The significance of this methodology is highlighted by its application to the synthesis of a potential CDK5 inhibitor, a bioactive compound.